There are two main types of hearing loss: conductive and sensorineural. Conductive hearing loss is caused by problems in the middle ear and outer ear, while sensorineural hearing loss is the result of inner ear problems.
Sensorineural hearing loss is often referred to as nerve deafness and is usually treatable only with hearing aids. Conductive hearing loss, on the other hand, can often be corrected surgically.
When Is Surgery an Option for Treating Hearing Loss?
A number of factors can cause conductive hearing loss. These include:
- Malformations of the outer or middle ear structures
- Chronic ear infections
- Fluid in the middle ear
- Perforated eardrum
- Benign tumors
- Impacted earwax
- Foreign objects in the ear
Many of these conditions can be corrected via surgery.
What Surgical Procedures Are Used to Treat Hearing Loss?
One of the most common types of surgical procedures is for the treatment of otosclerosis, an abnormal growth of bone on or around the stapes, the “stirrup bone” of the middle ear. This bony buildup prevents the stapes from vibrating as it normally would when stimulated by sound waves, causing hearing loss.
The procedure, called a stapedectomy, involves removal of the stapes and replacement with an artificial prosthesis. Surgery is usually completed in 90 minutes or less, and often the patient is able to go home the same day. It may take a month or so for results to appear, as there will be swelling and bruising that can impede hearing initially.
Ear tubes are tiny cylinders, made from plastic or other materials, which are surgically inserted into the eardrum to provide ventilation and drainage for children who experience chronic ear infections. They are meant to remain in place from six months to as long as several years; at some point they will either fall out on their own or will need to be surgically removed.
The surgery, known as a myringotomy, is an outpatient procedure performed under general anesthesia. Fluid behind the eardrum is suctioned out, a small incision is made in the eardrum, and the tube is inserted. The procedure is quick and painless, and usually takes no longer than 15 minutes.
Myringotomy is a common and safe procedure, and complications are rare. Occasionally, patients will experience a perforation of the eardrum, scarring or infection.
Eardrum perforations are most often caused by infection, injury or Eustachian tube disorders. Middle ear infections cause a buildup of pressure that may result in a ruptured eardrum as can inserting objects like bobby pins or Q-tips in the ear to clean wax.
While the majority of perforated eardrums heal on their own, some patients might have to undergo a surgical procedure called a tympanoplasty to repair the hole or tear in the eardrum.
Performed under general anesthesia, the hole in the eardrum is patched with a graft made of tissue from the ear or a man-made material. The surgeon will then place packing material on top of and behind the eardrum to keep the graft in place. Over several weeks the material will dissolve.
The surgery can take as little as 30 minutes or up to a few hours.
A middle ear infection can cause tiny air cells in the mastoid bone to fill up with pus. As the infection, known as mastoiditis spreads, the bone is destroyed, resulting in hearing loss. If antibiotics are unsuccessful in clearing up the infection, then mastoid surgery may be needed. Growths and disease may also require mastoid surgery.
A mastoidectomy involves drilling a hole in the mastoid bone and removing the infected air cells. This procedure is performed under general anesthesia, and many patients return home later the same day.
Afterward, your ears will be bandaged, and there may be stitches. You might experience headaches, discomfort and numbness. You’ll likely be prescribed pain medication and antibiotics, and will need to return after a few days to have your bandages and stitches removed. You’ll need to keep your ear free of water and avoid strenuous activity or anything that might create pressure on your ear (e.g. airplane travel).
Surgery to Remove Acoustic Neuromas
An acoustic neuroma is a benign tumor of the cranial nerve that connects the inner ear and the brain. Though noncancerous and typically slow-growing, it can affect both hearing and balance, and may cause hearing loss, tinnitus and dizziness.
If the tumor continues to grow and is causing symptoms, surgery may be needed. Performed under general anesthesia, the surgery involves removing the tumor through the inner ear or a window in the skull.
In some cases, the entire tumor may not be able to be completely removed. This occurs when the tumor is too close to important parts of the brain or facial nerve.
Types of Hearing Implants
Implantable Hearing Devices
Implantable hearing devices are surgically implanted instruments designed to improve the transmission of sound vibrations by directly stimulating the bones of the middle ear. There are several different types of implantable hearing devices including: cochlear implants, bone anchored hearing aids and auditory brainstem implants.
Cochlear implants are implanted surgically behind the ear and allow those who are profoundly deaf to understand speech and other sounds.
Cochlear implants generate an electrical signal that the brain interprets as sound. The implant has an external portion that sits behind the ear, consisting of a microphone, a speech processor and a transmitter. These work in tandem with the internal components, a receiver and an array of electrodes, which have been implanted in the ear.
Bone Anchored Hearing Devices
Like cochlear implants, this system bypasses the damaged hair cells in the auditory canal and middle ear, transmitting sound vibrations through the bones of the skull to the inner ear, where the nerve fibers responsible for hearing are stimulated.
A bone anchored hearing device is especially useful for patients with conductive hearing loss and single-sided deafness.
Auditory Brainstem Implants
Auditory brainstem implants (ABI) are similar in concept to cochlear implants, except they rely on electrodes placed directly on the brainstem that relay electronic signals to the brain. ABIs are less common, usually reserved for individuals whose auditory nerve does not function properly due to disease or trauma.